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kevenz
Reged: 04/25/11
Posts: 222
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World Rally 2 ?
#276712 - 02/20/12 10:42 PM


is this game actually playable? I'm stuck and waiting for coprocessor screen, I read it's caused by the suicide battery being dead.

but I've also seen many screenshot not taken from an arcade screen.

http://caesar.logiqx.com/php/emulator_game.php?id=mame&game=wrally2

Edit: just press 1 at the waiting screen to skip it.



FMecha
MAME's (Armchair) Motorsports Consultant
Reged: 01/18/09
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Re: World Rally 2 ? new [Re: kevenz]
#276790 - 02/21/12 05:10 PM


There's a unsolved bug that, if you crash, you are sent to nowhere. That, and the battery issue you mentioned, made the game GNW.



Lord Nightmare
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Reged: 03/08/04
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Re: World Rally 2 ? new [Re: FMecha]
#276793 - 02/21/12 05:13 PM


> There's a unsolved bug that, if you crash, you are sent to nowhere. That, and the
> battery issue you mentioned, made the game GNW.

As far as I'm aware, both of these issues are caused by the missing dallas ds5002 MCU data, which is destroyed when the suicide battery dies. The only way to get said data restored is to send the pcb back to Gaelco (and yes, they still repair these pcbs afaik).

LN



"When life gives you zombies... *CHA-CHIK!* ...you make zombie-ade!"



jonwil
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Re: World Rally 2 ? new [Re: Lord Nightmare]
#276799 - 02/21/12 05:48 PM


I wonder what that decapping guy would charge to read data from a DS5002FP (or if he even has the abillity to do so)



Lord Nightmare
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Re: World Rally 2 ? new [Re: jonwil]
#276800 - 02/21/12 06:08 PM


> I wonder what that decapping guy would charge to read data from a DS5002FP (or if he
> even has the abillity to do so)

Reading/bruteforcing a DS5002 is a huge mess, not for the faint of heart; read Markus Kuhn's papers about it.
https://www.cl.cam.ac.uk/~mgk25/kuhn-da.pdf
https://www.cl.cam.ac.uk/~mgk25/tamper.pdf

EDIT: Theoretically one could dump the encrypted sram data outside the ds5002 and try to crack the 24? bit key that is used to encrypt the address and data of every byte in the rom. The 24? bit key is NOT dumpable directly, in fact every time you program data into a ds5002 (it has a little intelhex-decoder rom inside to do this) it generates a new random key without operator intervention. It uses DES-like encryption according to kuhn, which probably means a 4-round fiestel network scheme like cps2 and the later naomi stuff use. Andreas and Nicola could maybe crack it, assuming we had a 'blank' ds5002 (technically all ds5002s are blank unless they have a battery attached, no flash inside) to program test data into and repeatedly dump the encrypted result.

LN

Edited by Lord Nightmare (02/21/12 06:56 PM)



"When life gives you zombies... *CHA-CHIK!* ...you make zombie-ade!"


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